Inner peace is the key: if you have inner peace, the external problems do not affect your deep sense of peace and tranquility. In that state of mind you can deal with situations with calmness and reason, while keeping your inner happiness. That is very important. Without this inner peace, no matter how comfortable your life is materially, you may still be worried, disturbed or unhappy because of circumstances.
----His Holiness, Tenzin Gyatso, the 14th Dalai Lama